I made some tests with a sculpted rock that I made in 3dCoat. It has no uvs and I wanted to texture it in Clarisse. I used triplanar mapping node for the base texture. With the help of the occlusion node I was able to give the cracks a darker and the edges a whiter appereance. On top I used procedural noises to get some more variations in the material. I'm quite happy with the result and will make more experiments. Maybe in future I don't need to do retopology again with rocks